Monday, April 24, 2017

Paleofest Report 2017

It’s time for my annual report of Paleofest in the Burpee
Museum in Rockford. Last year I skipped the report considering the high amount
of unreleased data as part of it, which is a shame since it was quite good.
This year there are fewer spoilers, but I did wait a month after the event. For
more on Paleofest itself, please check out my first report here: http://davidsamateurpalaeo.blogspot.com/2015/04/paleofest-2015-report.html

The first talk on Saturday was from Thomas Clements from the
University of Leicester. While McCoy et al’s proposal of Tullimonstrum’s
vertebrate affiliations and Sallan et al’s counterargument are given a great
deal of press, Clement and his team found an alternate line of evidence for
Tullimonstrum as a vertebrate. The Tully Monster, as a marine taxa exclusively
but well-sampled from the Mazon Creek formation, has been a mystery for 70
years, having been placed as a conodont, arthropod, mollusk, annelid, and
nematode.

What Clements et al did was use powerful electronic scans
and microscopes to compare it to other well-preserved animals. Turns out
melanosomes, organelles determining the pigment of a cell, are preserved, and
are especially concentrated in the eyes of fossilized organisms. The first step
was identifying the eyes of Tullimonstrum: the two long stalks coming perpendicularly
from the animal are tipped with melanosome clusters, suggesting that they were
the eyes of the animal. Finally, the melanosomes themselves were studied,
revealing a mix of both shapes of organelle, a condition only found in
vertebrates. While the lack of similar animals in the fossil record makes the
classification uncertain, Clements’ study makes a convincing case for the
animals being stem vertebrates or basal chordates instead of any invertebrate
group.

The second talk was by Julia McHugh of the University of
Western Colorado. Her study was on the anomalous survivors of the
Permian-Triassic mass extinction, particularly on the large temnospondyls that
were successful enough to survive to the middle of the Cretaceous period. The
Permian extinction was made up 2 land dieoffs and 3 oceanic dieoffs over the
period of a million years, killing off over 90% of species. At first it seems
as if the big predatory amphibians and herbivorous dicynodonts came off without
an impact, but McHugh discovered gaps and ghost lineages in the larger groups.

Apparently two groups of temnospondyls, the Euskelids and
Stereospondylids were extremely successful and diverse just before the
extinction, and coasted on their inertia. Paleohistology revealed there was
more variation in terms of growth cycles so that the animals could keep growing
during dry seasons. The variation in growth rate and cycles increased over the
Triassic. McHugh did not get to study therocephalians and dicynodonts to see if
they had similar adaptations or if they were doing different survival
strategies, but it’s interesting how it’s select few groups of terrestrial
macrofaunal that did very well in the apocalyptic event. Likewise, there was no
explanation why these adaptations failed them during the Triassic-Jurassic
extinction, but hopefully these other questions will be answered by followup
studies. It’s a fascinating answer that leads to further questions.

The next talk was by Susan Drymala of the University of
North Carolina on Triassic megapredators. These animals belong to the
paracrocodylomorph clade along with true crocodilians and other archosaurs. One
of these is the group called the Rauisuchians, containing the likes of
Saurosuchus, Ticinosuchus, Postosuchus and Teratosaurus. The group she studied
fit between the Rauisuchids and true crocodiles, containing the fish-eating
Qianosuchus, herbivorous Phyllodontosaurus and Effigia, and the macropredators
Carnufex and Renondavenator. Evidence of their predation on phytosaurus,
dinosaurs, dicynodonts, aetosaurs, and other paracrocodylomorphs shows they
were the top predators in their habitats.

In addition to archosaur traits of unidirectional airflow
and fast growth in warm climates, the rauisuchians and other
paracrocodylomorphs had upright stances due to their hips that curved around
the femurs without changing the shape of their femoral heads like dinosaurs.
It’s also possible that they were bipeds; the animals Poposaurus and
Postosuchus, due to their tiny forelimbs and powerful hindlimbs, have been
reconstructed in some studies as bipedal runners.It’s fascinating to see that other archosaurs
beat dinosaurs to their niches early, and this is a good companion to 2015’s
Paleofest on the Triassic.

A more problematic
talk was by Joseph Peterson of the University of Wisconsin, who runs the
Cleveland Lloyd Dinosaur quarry. It’s a poorly mapped formation of
limestone-covered mudstone containing hundreds of dinosaurs. While Camarosaurus
and Camptosaurus are the most common of the herbivores, the vast majority of
fossils belong to subadult Allosaurus. It’s paradoxical how many more
Allosaurus there are than other fauna. There are barite and calcite modules
showing a dry habitat, but there is no abrasion from wind or water erosion. The
bones are jumbled and disassociated, but individually in great shape.

Two theories have been proposed to explain the quarry, but
Peterson argues against both of them. The quarry has disarticulations like a
drought assemblage, but there is no distortion from exposure or splintering
from desiccation. There’s no hydraulic influence and predators are extremely
abundant like a predator trap, but there is no articulation or traces of
feeding on the bones. A chemical study revealed sulfies and pyrite in the site,
with abundant charophyte algae but no freshwater plants. Geochemistry shows
heavy metals present, but they could just as easily be from the decaying
corpses than the cause of the death.Peterson suggests the site was an ephemeral pond with multiple
depositions, but the characteristics still don’t fit. Why so many animals? Why
no marks of scavenging or desiccation? Why so many juvenile predators? To make
matters worse, Peterson does not support his proposal with modern examples. The
Cleveland Lloyd quarry is an enigma, and this study raises more questions than
it answers.

The next talk is a bit better-there is no attempt to try to
untangle the mess here. Karen Poole talks iguanodonts, and ornithopods in
general. The classification is confusing and the cladistics here is very
complex.The most basal of these bipedal
beaked herbivores were the Hypsilophodonts, a probably parphyletic group of
small basal ornithopods from the early Cretaceous of the entire globe. A more
derived group were the Thesecelosaurs from early Cretaceous Asia and late
Cretaceous North America.The next
derived group were the Rhabdodonts, a surprisingly successful group that
started in Europe and made it to North America and Australia for brief bits but
survived in the European islands until the mass extinction.

It’s difficult to tell if the Camptosaurs and Dryosaurs are
more or less derived; the Camptosaurs seem to have started in the Middle
Jurassic European islands and continued into the middle Cretaceous in North
America. There seems to be a new clade of long-armed, robust boned, huge-spiked
ankylopollexians; this unnamed clade contains Barilium and Hypselospinus from
West Europe, Bolong and Jinszhousaurus from China, and Lurdosaurus from North
Africa. Just outside the Iguanodontines is Lurdusaurus’ compatriot Ouranosaurus
and the American Hippodraco. It seems that these families of ornithopods freely
intermingled, species popping in and out replacing each other. Iguanodontinae
itself, defined by high-crowned teeth that are especially narrow in the maxillia,
contains Iguanodon itself with later species such as the Chinese counterpart
Equijubus, the Japanese Fukuisaurus, and the Spanish Proa.More derived species contain Mantellisaurus,
Probactosaurus, Althirhinus, and Eolambia. The Bactrosaurs, including the
European Telmatosaurus and Tethyhadros (the Europeans outlived the rest of the
family) seem to be transition between the Iguanodonts and the spikeless,
toothier hadrosaurs.

Following land vertebrates comes marine invertebrates, albeit
from the same period of time. In this case, Rex Hanger of the University of
Wisconsin in Whitewater discussed reefs of the Niobara found in Texas. Said
reefs were made by rudists, giant bivalves, instead of corals. The tropical
fauna also included Echinoids, sharks, the fish Gyrodus, Snails, cephalopods,
and oysters, all extremely well-preserved, abundant, and diagnostic. The index
fossil is the ammoniate Oxytheropidopteryx. The silified preservation shows
unique environmental conditions; the Karamichi member is a low-oxygen habitat
that preserves micromorphs of the known species encased in pyrites. A
fascinating place, despite it being invertebrate based

The next talk was far more conventional, with Eric Snively
of the University of Wisconsin-La Crosse talking about Tyrannosaurus
biomechanics. The specifics are still under wraps, but his conclusion is that
Tyrannosaurs owe their amazing success due to their ability to exploit multiple
niches over their lifetime while remaining the fastest and more agile dinosaurs
of their size.

Eugenia Gold of Stony Brook University gave a travelogue
instead of an academic talk, but it was still educational. For all expeditions,
I learned, I must remember to back a mechanic, a lighter, food, water, hammer,
spare tires, and, in case Mark Norell is part of it, Gnocchi. You can see her
website and twitter for more on her experiences. http://www.drneurosaurus.com/

The last talk of the day was the most entertaining, by Dr.
Thomas Holtz of the University of Maryland. His topic was on dinosaur cursoriality;
the adaptations required for extreme speed. In terms of speed, we’re pretty
pathetic-scoring 10.45 meters per second with our best athletes-dogs, ostrich,
horses, and pronghorn can hit more than 20 meters per second. An example of a
cursorial adaptation is limb shape: the longer the fibula, tibia, and
metacarpals and metatarsals are, the faster the animal can move. There’s also a
big of differences in what aspect a cursorial adaptation is for: speed,
acceleration, or home range.

Theropod dinosaurs, particularly coelurosaurs, have
pinched-in feet where some of the metacarpals and tarsals are fused together
for a single, strong structure: the acrometatarsus. In Holtz’s study, groups
with cursorial adaptations include the odd gracile Elaphrosaurs from Jurassic
Gondwana, the surpsingly nimble tyrannosaurs, the super-cursorial ornithomimids
and alvarezsaurids, and to a lesser extent oviraptors and troodonts. There’s a
trend of increased cursoriality as the Cretaceous goes on, with Troodon,
Ornithomimus, and Tyrannosaurus being quite well adapted for running.Therizinosaurs are the exception among
coleurosaurs, being probably unable to run. It seems that most dinosaurs were
growing faster and faster through the Cretaceous, even among more primitive groups
such as the Abelisaurid ceratosaurs and the Megaraptoran carnosaurs.

Sunday’s talks began by not a scientific study, but Sarah
Boessenecker’s accounts of her curatorial duties at Charleston College’s
Museum. There’s a large amount of great specimens, but it’s heavily reliant on
local volunteers and fundraisers. There’s not much else to say about this one,
except that I strongly encourage everyone reading this to visit and support
their local museums. http://geology.cofc.edu/natural-history-museum/

An environmental study of a fossil bed was next. Marie
Lorente of Reservoir Labs examined a bed in the famous Hell Creek formation.
This place was called the Ninja Turtle quarry as the first fossils were four
turtles. Palynological studies revealed a great deal of pollen and spores,
while the fossils are mostly freshwater turtles. That is, for the first place.
The underlying layer has very few pollen, no turtles, and is almost entirely
saltwater dinoflagellates. This dramatic turnover may be the result of a tsunami.
The ideas of a warming event or volcanic event don’t fit into the date of the
find; the late Cretaceous was cooling and the turnover happened in-between
volcanic events. Likewise, the K-T comet was not responsible as this happened a
million years before that. This narrows it down to a tsunami or similar oceanic
flooding as seismic events pushed saltwater out of the ever-narrowing interior
seaway.

One of my favorite talks was by Victoria Arbour of the Royal
Ontario Museum. She noticed that for most tetrapods, weapons are mounted on the
head, and very few on the tail. She decided to make a study of fossil groups
with tail clubs and similar weapons. Today, tail weapons are the spiny tails of
porcupines, sharp-scaled Pangolin tails, lizards with spiked whips or clubs as
their tails, and muscular, armored tails of crocodiles. The fossil groups examined are the glyptodont
armadillos, meilonid turtles, and herbivorous dinosaurs.Stegosaurs, for example, have very strong
flexible tail, with the spikes (or thagomizer) being set into the skin of the
animal. In contrast, Ankylosaurs have fused tail veretebrae. The clubtailed
sauropods only have the last few tail vertebrae fused. Glyptodonts have unfused
bones but their osteoderms are fused into interlocking rings and tubes with the
muscle underlying them. Meilonia has a straightforward flail, with no fusion in
the entire tail. Club durability has been mechanically tested-clubs of both
ankylosaurs and glyptodonts were sturdy enough to crunch into bones.

The main topic studied was how did the club evolve-handle
first? Knob first? Or in tandem? Earlier ankylosaurs help flesh out the story:
Gobisaurus had no tail club, but had fused tail vertebrae. Liaoningosaurus, an
odd fish-eating ankylosaur, had long spinous processes. Dyoplosaurus,
predecessor to Scolosaurus and Euoplocephalus, possessed a small club compared
to its successors.Glyptodons seem to
have had the same situation, culiminating in the Pleistocene Doedicurus and Eleutherocercus
with their mace tails. There seems to be
a correlation in evolutionary adaptations that produce tail maces: body armor, head spikes, weight over 500 kg,
quadrupeds, herbivores, stiff thoraxes, and wide pelvises.The selection pressure for such weapons could
be from Tyrannosaurs or for fights for matesA study of tyrannosaur bones and ankylosaur armor needs to be done to
identify if there are any fractures from tail impacts. On her request, I will
use the hashtag #ankylosaurfightclub to identify depictions of ankylosaurs
fighting anything.

An exciting talk was by the Field Museum’s dinosaur
paleontologist, Peter Mackovicky. Mackovicky, when he is not excavating the
upper Cedar Mountain Formation or joining the rest of Tyrannosaur
paleontologists in the Late Cretaceous, has spent many summers in
Antarctica.As early as the ill-fated
Scott expedition and its plant fossils, paleontologists have found tantalizing
glimpses of a tropical continent far from the icy wasteland of the past era.
McMurdo Station, as well as anchoring zoological, meteorological, and
climatological expeditions and studies, also acts as a base for paleontology.
The central mountains, particularly Mt. Kirkpatrick, have rocks of the Triassic
and Jurassic eras, complete with anmal fossils. The early Triassic layer
contains Lystrosaurus and other animals similar to South Africa’s Karoo
formation, showing the passage of Gondwanan fauna even after the breakup of
Pangea. This is followed by a late Triassic fauna, again similar to South
Africa’s lower Elliott formation’s; the cynodont Thrinaxodon is known from
South Africa while the huge temnospondyl predators Kryostega and Antarctosuchus
are unique. It is the Hanson formation, first discovered by David Elliot on the
peaks of Mt. Kirkpatrick, that contains Jurassic dinosaurs

The Field Museum has been joined by the University of
Wisconsin, the University of Alberta, Augusta College, and their guide Peter
Braddock on their expeditions; they have uncovered the large predatory dinosaur
Crylophosaurus and the sauropodomorph Glacialosaurus in the past. New finds
complete Crylophosaurus’ anatomy with another individual, more Glacialosaurus,
and add more fascinating animals: other sauropodomorphs “Jolly Roger” and an
isolated Sacrum (both of which, like Glacialosaurus, have counterparts in the
upper Elliot), a molar of a tritylodont (a small herbivorous cynodont), and the
humerus of a basal pterosaur. I’m very excited to learn more about these
animals, and especially about next year’s temporary exhibit at the Field Museum
showcasing Mackovicky’s finds.

Katie Tremaine followed this with a followup on previous
studies. Last year featured no fewer than two talks on the same subject. You
see, some Tyrannosaur specimens have been found with medullary bone, tissue
buildup within the long bones (femurs and humeri). In modern birds, the buildup
is only found in female birds that ovulate. This so far is the only way to sex
a dinosaur; sexual dimorphism seems not to be significant among most dinosaur
species at least in terms of bone size and structure. The calcium within the
bone is produced to be used for the forming of eggshells, so only a dinosaur
that is going to lay is going to have this buildup. This is the main flaw with
this method: Jane and Sue, for example, could be either sex, as they could
either be males or females that are not about to lay. What Tremaine
accomplished is chemically staining the calcium, taking the bones into X-ray,
and making sure that the bone buildup cannot be from a different physical state
or reason. So far, only Petey, a teenager, has been found to be a female.

The next talk was farcical: talking mostly about the
ridiculous “Toroceratops” model in which all Torosaurus are identified as
mature Triceratops. It is a pet theory of Horner and Scanella at the Museum of
the Rockies, but their lumping agenda will be discussed elsewhere. Suffice to
say, their methodology is flawed, their logic is convoluted, their evidence
weak, and their bias obvious.

Thankfully, the next talk was by David Grossnickle, of the
University of Chicago. What he did was a clever study on studying mammalian
diversity in all permutations during the Mesozoic into the extinction.
Morphometric parameters of mammalian teeth (which are not only significant
given mammal tooth evolution, but inherently easier to find than body fossils)
were plotted on various scales. While glimpses of mammalian diversity are shown
by the rare full body fossil, such as the badgerlike Gobiconodont Repenomamus,
one must take subtler approaches to determine diversity using all known data.

There seems to have been a fair amount of therian radiation
in the late Cretaceous based on tooth geometry. While there is an increase
after the K-Pg extinction, it seems to have begun during the age of dinosaurs.
Size, species, and diet diversity increase over time, but the differences also
become subtler with a greater continuity within lineages. Interestingly enough,
this also follows a path of angiosperm and insect radiation during the
Cretaceous. As flowering plants become more successful (stimulating in turn
dinosaur evolution), insects radiate to exploit it, and mammals diversify to
exploit them. It’s a chain reaction begun by the evolution of flowers leading
to an incredible diversity of life on every tropic level.It’s a fascinating look into evolution.

Mark Loewen of the Natural History Museum of Utah talked
about familiar territory for me considering my experience with the Field
Museum: the Great Lakes of Utah. Back in the Eocene, four large freshwater
bodies formed the heart of the tropical Green River Formation: Gosiute, Uinta,
Claron, and Fossil. In this tropical land, the rhinolike Uintatheres and
bearlike bird Gastornis ruled. The tiny horse Protorohippus ate fruits and
leaves in the dense rainforest, stalked by the catlike Patriofelis. The first
American bat Icaronycteris,
lacking echolocation, would have to compete with the birds for insects and
other small prey.In the water, a
flightless rail similar to those of the Ice Age pacific shared the habitat with
the incredibly successful Presbyornis, boavid snakes, turtles, paddlefish, huge
gar, the common fish Knightia, Diplomystus and Priscara, all being predated by
the crocodile Borealsuchus. All of these were perfectly preserved, down to the
feathers and scales.

The reason for the preservation is the calcite deposits on
the shore-the calcium dissolves in the lake, and when it blends with the
organic material, it forms a hard, distinct fossil. The lake lived and died due
to the Rocky Mountain orgeny-the uplift of the earth formed high bowls and
streams ran from the young mountains to feed them, but the continued lifting
cut the streams as well, and the Oligocene drying destroyed the entire habitat.
I would strongly recommend Lance Grande’s book on Fossil Lake for more information.

The next talk has a special connection to me: in my human
evolution class, my teacher proposed a new technique on determining fossil
environments via the teeth of bovids present. Allison Bormet of the University
of Illinois Bloomington chose a different approach: the limbs of ruminants. Her
beginning using living ruminants ran into problems early: zoo ruminants show a
lot of individual variation, and their limb bones are shaped by their current
environments which have little to do with their wild habitats. Instead, she
went to the IUCN and its species distribution map, which helped place bovid
species in proper environmental contexts.

The good news is that fossil ruminants all have present
analogues. The bad news is that their limbs don’t preserve as often as their
teeth.Fortunately, ungals are tough
little bones, especially for relatively large digitigrade cursorial animals. Bormet
managed to even work out an equation: Body size X Vegetation cover=ungal
size.Of course, this is just the
beginning of the study, and she has yet to correlate it to tooth studies and
apply it to extinct taxa, but it shows a lot of promise and I can’t wait to
hear what comes next.

Dr Robert Boessenecker
of the University of Charleston finished Paleofest with his lecture of
Mysticete, or baleen whale, evolution. Mysticete fossils fortunately have very
unique and diagnostic ears. The transitional families between the Eocene
Archaeocetes and Miocene Mysticetes, he explained, are the Aetiocetids and then
the Eomysticetids in the Oligocene. The Aetiocetes retained the teeth of the
Archaeocetes, but the Eomysticetids lost their teeth. Like other whale
families, they are well-represented in North Carolina, Australia, Baja
California, and especially Japan and New Zealand

New
Zealand’s Oligocene and Miocene Otekaike and Kokoamu formations are rich in
whale fossils, particularly basal Eomysticetes that still have trace teeth like
Mataponui, Tokarahia, and Waharoa. They are at the point where the Mysticetes
begin to evolve temporomandibular joints that sacrifice biting strength from
the Archaeocetes for the ability to expand their jaws to a wider gape. The
closest living relatives to them are the grey and right whales, the most basal
baleen whales. The talk was a fascinating look into the amazing diversity of
whale genera during the late Oligocene of New Zealand, making it the grand
finale to this year’s Paleofest.

Once again, I recommend Paleofest-there’s something for
everyone! It’s worth the drive out to Rockford and the hefty price tag for this
annual celebration of paleontology. I encourage my readers from the Midwestern
US to give it a visit. I know I’ll be there next year! See you then!

5 comments:

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About Me

Hi everyone! You may know me already, but 99% of you won't. I've decided to make a blog for myself. I'm a anthropology student who has returned to his original passion for palaeontology. Ever since I was little, I've been fascinated with the weird and wonderful animals that have inhabited our planet and I've made this blog to keep this in my mind and hopefully in yours. Most people blog about their interests, and while I've got a range of interests-see history and anthropology above, not to mention zoology, astronomy, art, cooking, science fiction and fantasy films and literature, and a myriad of others, the one I want to do for a living is the study of Earth's ancient past.

On this blog I'll review papers, talk about fossils, museums, and taxa, review art, film, literature, and our culture's view of paleontology, and share memories and insights. I've been inspired by the far better blogs of professional palaeontologists, and I'll share them as time goes on. I'm also open to requests and questions of opinions, the latest palaeo news, and discussions with other fans informal and professional.

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